Aitor Karanka has praised the efforts of Dimi Konstantopoulos after Boro reached another defensive milestone against Burnley on Tuesday.
Boro haven't conceded in the league in the last five games and the Teessiders have the best goal difference in the division.
Dimi has played a big part of that solidity in the Championship, and with the keeper having made 20 league appearances this season, a clause in his contract that means his stay on Teesside is renewed for another year.
The former Hartlepool man was way down the pecking order in terms of selection when Karanka arrived at Boro three years ago.
However, Dimi's strong performances have meant the Greek has seized his place as Boro's number one and Karanka has hailed the keeper as an example to others.
"He's always calm," said Karanka "He's set a good example for everybody.
"When I arrived here he was third choice keeper and was always trying to take advantage of his chances.
"He had his chance first season and lost that because I put Tomas in goal the second season but he kept working in the same way.
"Now he has taken his chance again this season and is playing really well. When Tomas plays he does well in the cup."